It is proposed to improve the growth and maintenance of cultured cells of Blattella germanica (L.), isolate intracellular bacterial symbiotes Blattabacterium cuenoti Hollande & Favre from host insects, and infect the cultured cells with the pure symbiotes. Work will be done on growth kinetics of the symbiote in ovaries, embryos, and if possible in vitro. Routes of embryonic infection will be studied with electron microscopy.